The present invention relates to an output conveyor unit for rigid hinged-lid cigarette packing machines.
Known cigarette packing machines of the aforementioned type feature an output conveyor comprising a first and second conveyor cooperating at a given point of tangency.
The first conveyor normally consists of a packing wheel having a number of peripheral seats, which, as the wheel is rotated about its axis, are fed through a loading station where each seat is fed with a packing blank and a preformed group of cigarettes. Each group is substantially in the form of a rectangular parallelepipedon, and is so inserted inside the seat on the packing wheel as to travel perpendicular to its smaller lateral surface, with its larger lateral surface facing outwards, which larger surface, when the packet is completed, extends in contact with a front portion of the packet partially defined by a movable front portion of the lid.
Each blank is folded partially in a U about the group as it is inserted inside the seat, and is gummed as required and gradually folded by the packing wheel into a semifinished packet, which is normally completed by a final folding operation as the packet is transferred from the packing wheel to a respective seat on the second conveyor.
The second conveyor normally consists of stabilizing or drying conveyor along which the gummed portions of each packet are at least partially dried for achieving a firm shape of the packet.
Known packing machines of the aforementioned type normally involve a certain amount of inaccuracy in the positioning of the overlapping gummed portions of the packets, which frequently results in partial or faulty closure of the lids.
Such inaccuracy is normally due to the seats on the second conveyor being oversized axially to prevent chafing, i.e. so as to cooperate loosely with the axial end surfaces of the packets, which clearance, however, also results at times in imperfect shaping of the lids of the packets.